Vapor line for oil tanks



- 1,613 269 Jan. 4, 1927. J M EVANS VAPOR LINE FOR 011, TANKS Filed Nov. 20, 1924 JOHN M. EVANS.

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Patented Jan. 4, 1927.

UNITED STATES PATENT OFFICE.

JOHN'M. EVANS, OF SAN FRANCISCO, CALIFORNTA, ASSIGNOR, BY MESIN'E ASSIGN- MENUS. T0 STANDARD OIL COMPANY OF CALIFORNIA, OF SAN FRANCISGO, CALI- FORNIA. A CORPORATION OF DELAWARE.

VAPOR LINE non OIL TANKS.

Application filed November This invention relates to vapor lines for oil tanks and is more particularly directed to an apparatus for the reduction of evaporation losses from working tanks containing volatile fluids" such as gasoline, crude petroleum, and the like.

In a tank for the storage of crude oil, gasoline or the like, the loss from vaporization is a serious'factor in the storage of such liquids. 4 I

When a tank is being'tilled the air above the surface of the liquid becomes saturated with the light and most. valuable contents of the oil and as the filling of the tank proceeds this air saturated with the light vapors must be forced outward through the top of the tank which results in a very considerable loss.

ln en'iptying a tank, unless means are provided for allowing gas or air to enter the tank, a vacuum is created within the tank. If the hatch or manhole inthe top of the tank is openeda-nd air drawn into the tank, the air becomes saturated with the vapor and in filling the tank again, as above pointcd out, the vapor contained in this air is completely lost. Such forcing of air saturated with volatile vapors outward from the top of the tank produces a great tire hazard.

This invention, therefore, relates to the operation of pairs of those tanks, usually termed working tanks, or there may be several tanks in the group, so that as one tank is being emptied and another tank is being filled the vapor expelled from the tank being -filled is conveyed to the tank being emptied to supply a portion or all of the gas necessary to relieve the vacuum produced therein.

This invention consists primarily of a pipe line carrying the vapor in conjunction with which vacuum and pressure relief valves to regulate the pressure in the tanks and other apurtenances are embodied herein to reduce the hazard from fire and from unsafe pressure. I

The object of this invention is to produce a new and improved system for conveying the vapor from a tank being filled to a tank being emptied for the preservation of the valuable constituents of that vapor.

An object of this invention is to provide a newand improved system of vapor or gas transportation between working tanks, in

20. 1924. Serial No. 751.103.-

WlllCll means are provided to closely regulate the pressure in the tanks.

Other objects and advantages of this invention willbe apparent from the detailed descriptionof a preferred embodiment there of as illustrated in the accompanying drawings.

in the drawings:

Figure 1 is a side elevation of a vapor line between volatile liquid tanks, embodying this invention. I r

Fig. 2 is'an enlarged side elevation partly in section of a pressure and vacuum relief means embodied in this invention.

In the drawings, 1 indicates a pipe line of suitable size conveying vapor between the tanks 9., 2 in which line 1 pressure and relief valves 3, 3 and 4 are adapted to control the pressure in the tanks 2, 2 and in line .l and to allow the escape of excess vapors, which pressure and vacuum relief valves3, 3 and 4 are the subject of the co-pending application of John Kuhl, filed November 25, 1924, Serial Number 752,276., 7

The said pressure and vacuum relief valves are mounted on each tank, as at 5 and at a centrally located point (3 in the line 1, or they may be placed only on one or more of the tanks 2, or only at the central point 6. However, it is preferred for safety to mount such a valve on each tank 2 and at the centrally located point 6'. With this arrange vment, it is preferable to have the relief valves 3, 3 set to open at pressure or vacuum of about one inch of Water and the central valve tset'to open at about one-half inch of water. With this differential and proper line sizes all, or most, of the excess vapor which must be forced from the system will be discharged at the central point 6, which being located well away from the tanks 2, 2 minimizes fire hazard. It, however, being understood that if desired the excess vapors discharged at this point may be conveyed by another pipe to any suitable recovery system, such as a compressor plant or refrigeration plant, or otherwise disposed of. If the quantity of such vapor is too great for the central valve 4 to handle, or the said valve 4 becomes inoperative for any cause, the discharge will occur thrdugh the tank pressure relief valves 3. The same is true of the operation of the central and tank vacuum relief valve s.

Thepressure and vacuum relief valves 3, 3 and 4, comprise a body .16 having tapered openings 17, 17 and 18, 18 in the top and bottom thereof for holding the seats 19 of vacuum and pressure relief valves20 and making agas-tight connection between the main body and valve seat. A cylindrical opening 21 is bored in the top of the body 16 near the centerthereof and a similar opening 22 is bored in the bottom of the body ,,16 to register with the bore 21. The said openings 21 and 22 are adapted to receive a cylindrical screen flash arrester f 23 tofore ,referped to. The pressure and vacuuin relief valves 20 are of the liquid seal type and are particularly described in that v co-pending, application of John Kuhl, above referred to, and comprises a seat 19 having a circular groove'25 adapted to be filled with mercury or similar fluid and have a cross or connecting web 26, having a central bore 27 through which a valve stem 28 is adapted to pass. -Secured to the upper end of the valve stem 28 is a valve head 29 adapted to seat within the mercury groove 25. Secured to a cylindrical boss 30 of the seat 19 by any suitable device, such asa cap screw 31, is adash pot 32. Means are provided for guiding the valve stem28 within the dash pct 32 which means are generally indicated at 33. A pin 34- pas'ses through the valve stem 28 and is adapted to engage the inner side of the bore 27 so" as to limit the opening of the valve'20. I

In combination with the vapor line 1 the valves 3,3 and 4, and as an integral art of the system, are flame arresters 7 w ich are the subject of that co-pending application of Hubert H. Hall, filed November 28, 1924, Serial Number 754,452, (Patent No. 1,586,195, granted May 25, 1926).which are designed to prevent a fia e or explosive force from traveling through the pipe line 1 They may be located at. a convenient point or points in the line 1, such as just inside the firebank 8 surrounding each tank drainage of the condensate without loss. of

the vapor formed or the admission of air into the system. Small pipe lines 11 of about one inch size may lie-installed connected to each tank roof as at 12 and meetingat some convenientpoint 13 connect with instruments 14 which indicate or record thezpressure or vacuum existing infthe tanks 2 and if desired at other points in the system. Also at this junction electric connections may be provided to operate a bell or born 15 or other alarm device whenever excessive pressure or vacuum exists in the tanks.

Having fully described a preferred embodiment of the invention, it is to be understood that it is not intended to limit the in vention to the exact-construction and details herein set forth which may obviously be varied within'the spirit ofthe appended claim.

I claim: In a vapor recovery system, a pair of spaced working tanks, a pipe line adapted to convey vapor between the working tanks,

.means connected to a low point of the said pipe line for the drainage of condensate therefrom. r

pressure relief means within the line. and

Signed at San Francisco, California, this 3rd day of November, 1924.

JO HN M. EVANS. 

